Conventional wheelchairs provide equipment for use by disabled persons in order to be mobile and to increase the opportunities of disabled persons to participate more fully in daily activities. Conventional wheelchairs are typically manufactured of metal tubes which are cut to length, bent into shape, and welded together to form a tubular frame that supports a seat and back. Wheels connected to the frame provide mobility. Push handles attach to the back of the frame for pushing the wheelchair or controlling its direction of the movement. The purpose of wheelchairs is to provide equipment which solves disability-related problems, so that disabled persons can more easily participate in everyday life activities while minimizing the problems created by the equipment.
Generally, wheelchairs for profoundly immobilized persons are custom-built using specific measurements of the particular person to use the wheelchair. The measurements are used to determine the particular width, depth, and height of tie frame, the seat, and the seat back for the wheelchair. Because of the many combinations of sizes, it is expensive to maintain inventories of specific sized component parts. Accordingly, manufacturers of wheelchairs cut elongated tubular members to size based on a customized specification for the particular individual. The tubes are assembled into a frame of a specific design. Production of an individual wheelchair is complex and slow because custom parts have to be manufactured. Also, due to personalized customization of the dimensions of a wheelchair, it is not practical to maintain inventories of completed frames. Similarly, the large number of variations and combinations pre-vent retailers of wheelchairs from holding wheelchairs in inventory. Further, there often is a lag time of many weeks between ordering a custom wheelchair and delivery of the wheelchair to the user.
During manufacture, the frame members are typically joined together by welding. The seats, backs, pads, push handles and wheels are then conventionally connected to the frame using clamps, tubular connectors, latches, and bolts with nuts. While these secure the components to the frame, the connectors must be loosened, removed, and repositioned for adjusting the orientation and position of the components. For aides to wheelchair users who are not skilled in mechanics, operation of these connectors may be difficult, awkward, and frustrating. Also, the connectors must be loosened or removed in order to disassemble the wheelchair for transport in cars.
Further, the tubular frame and various connectors make conventional wheelchairs difficult to “grow” in order to accommodate the physical growth of the user as well as accommodate the different situations that a user will be exposed to during daily life. Among these situations can be the need to be able to fit under a table, gain access to a sink, reach for things in cupboards, change the comfort position for typing, watching television, engage in conversation and the like.
From U.S. Pat. No. 5,727,802 a wheelchair is known which has an upper and a lower frame. At the rear of the wheelchair a shock absorber is provided arranged between the upper and lower frames. A pivotal connection is provided at a connection point between the upper and lower frames in the front end of the wheelchair. In this manner a certain amount of shock absorption is built into the construction.
Disabled persons who look to wheelchairs for mobility also are dependent on the wheelchair for bodily support. It is important that the wheelchair be lightweight and easily maneuverable, in order to conserve the energy of the person. Also, the seat and back should be easily adjustable to provide proper posture and comfort. Improper seating is not only uncomfortable but may create additional physical problems for the person using the chair. The width, height, depth, and tilt of the seat as well as the width, height, and tilt angle of the back of the seat, affect proper seating. Proper adjustments of the seating variables, together with proper sizing of the wheelchair contributes to a more neutral skeletal alignment and may impede the progression of skeletal deformities and muscle contracture, better manage seating pressures and reducing the potential for pressure sores, improve the seating stability of the occupant, increase sitting tolerance through increased comfort, and decrease fatigue. The tubular frame however often interferes with attachment and adjustment of the pads and abductors which may be critical to properly supporting the user in the wheelchair.
Accordingly, there is a need in the art for improved wheelchairs that are readily assembled, disassembled, adjusted, and used for and by disabled persons. It is to such that the present invention is directed.